Liquid crystal compound

ABSTRACT

The present invention is an optically active liquid crystal compound shown in the following general formula; ##STR1## [wherein, A and B respectively show one of --, --O--, ##STR2## (-- shows direct bond), one of R 1  and R 2  shows direct chain alkyl group and the other one shows either alkyl group having asymmetric carbon atom or alkoxy alkyl group having asymmetric carbon atom and ether bonding. Also, onto the asymmetric carbon atom, one of the groups --CH 3 , --CN, --Cl is added.] 
     It is clear that there are many compounds in these liquid crystal compounds, that show Sm C* phase in a wide temperature range close to room temperature and that have high response speed.

FIELD OF THE INVENTION

The present invention is related to a new liquid crystal compound usefulfor electric optical elements, utilizing the response of a ferroelectricsmectic liquid crystal to an electric field.

BACKGROUND OF THE INVENTION

Liquid crystals have been adapted already as the electric opticalelements for many kinds of devices such as display devices, shutteralley for a printer, shutters for cameras, and are actuated in thedisplay of watches and table calculators.

Most of the liquid crystal display elements presently actualized areelements utilizing the dielectric orientation efficiency of a nematicliquid crystal or a cholesteric liquid crystal. But, concerning theexpected requirements for display elements with many picture elements,there are such problems as, an insufficient response ability, a contrastnot able to obtain the necessary drive margin, and an insufficientvisual angle characteristic. Therefore, extensive research anddevelopment of the TFT panel or MOS panel that forms the switchingelement in each picture element is being carried out.

In this state, Clark et al (U.S. Pat. No. 4,367,924) conceived new aliquid crystal element with new display principle, utilizing the smecticphase, which cures the above defects of the liquid crystal element. Theexplanation of this new element is as follows;

FIG. 1 is a typical diagram of the smectic C* phase or the smectic Hphase. The liquid crystal is composed of molecule layers 1, and in eachof the layers, the average direction of the molecule axis is inclined odegrees in the vertical direction to the layers. Meyer et al teaches ina thesis titled "Ferroelectric liquid crystal" of "Physical Journal" (LeJournal de Physique Vol. 36, March, 1975 PPL-69 to L-71), that, theSmectic C* or H phase composed of an optically active molecule generallyhas an electric dipole density P and is ferroelectric. This dipoledensity P is vertical to the molecule direction n, and is parallel tothe layer surface of the smectic. What they teach is adaptable to thesmectic H phase, but in the H phase, the viscosity to the rotationaround the axis vertical to the layer, becomes large. The existence ofelectric dipoles in these chiral smectic liquid crystals gives astronger coupling force to the electric field, than that of dielectricanisotropy. Furthermore, it can be said that this coupling force has apolarity characteristic, in the sense that the favorable direction of Pis the parallel direction to electric field E, and so, by reversing thedirection of the applied electric field, the direction of P can also bereversed.

Therefore, by reversing the electric field, as shown in FIG. 2, thedirection of the molecule can be controlled by moving the molecule alongthe cone (the angle 2° of this cone is hereinafter referred to as thecone angle). Then, by detecting the variation of the average moleculeaxis direction with two polarizers, the liquid crystal element can beutilized an electric optical element.

Because this electric optical element which utilizes the response of theSmectic C or H phase to an electric field, holds a coupling forcebetween its spontaneous polarization and the electric field, a forcewhich is 3 or 4 orders larger than the coupling force of dielectricanisotropy, compared to TN type liquid crystal element, this electricoptical element has an efficient high speed response characteristic, andit can also have a memorizing characteristic by selecting theappropriate orientation control; thus it is expected to be adapted as ahigh speed optical shutter or as a display with a large capacity forinformation.

Meanwhile, many kinds of chiral smectic liquid crystal material having aferroelectric characteristic have been studied and synthesized. Thefirst synthesized ferroelectric liquid crystal is called DOBAMBC.

p-Decyloxybenzilidene-p'-amino-2- methylbutyl cinnamate, and manycompounds of this series of liquid crystal compositions, shown in thefollowing formula, have been synthesized for research concerningferroelectric liquid crystals. ##STR3## wherein X represents H, Cl, orCN and Y represents Cl.

But as this series of liquid crystal shows the chiral smectic phase at atemperature higher than room temperature, there are such defects as, notbeing able to be used at room temperature, it is a Schiff base series,it is decomposed with water, and its stability is bad.

As a developed compound of this series, a Schiff base series chiralsmectic liquid crystal compound in which the hydroxyl group isintroduced into one of the benzene rings, and provides a hydrogen bondin the molecule, as shown in the following general formula, wasannounced by B. I. Ostrovskii ("ferroelectric", 24,1980,309) and by A.Hallsby (Molecular crystals and liquid crystals, Letter 82,1982,61), andthis developed compound has been given attention as being a compoundshowing the smectic C* phase at a wide range of temperature includingroom temperature. ##STR4##

As this compound also has a hydrogen bond within the molecule, it ishardly decomposed with water and has much better stability a compared togeneral Shiff series of liquid crystal. But as a practical matter, it isrequired that the compound not crystallize at a temperature below 0° C.,and so the liquid crystal material synthesized with compounds of thisseries are still not completely satisfactory.

Other than this, a liquid crystal material of the azoxy series wasannounced by P. Keller et al ([Annales de physique]1978, 139) but withthis compound too, there are such practical problems as not havingefficient characteristics concerning the temperature range, and being adeep yellow color.

Among these compounds, an ester series liquid crystal having a goodstability and widely practiced as a TN type liquid crystal material hasbeen given much attention. In a well known document, a liquid crystalcompound has been disclosed having a structure of the formula; ##STR5##

This formula was announced by B. I. Ostrovskii et al, as being materialshowing the chiral smectic liquid crystal at a temperature range closeto room temperature. Also, G. W. Gray et al announced in "MolecularCrystal and Liquid Crystal" 37 (1976) 189, (1978) 37, a biphenyl esterseries of compounds showing chiral smectic liquid crystal at a hightemperature range.

As stated above, at present, a liquid crystal that shows a chiralsmectic phase over a wide range of temperature including the practicalcondition of room temperature, does not exist, and, even with materialsshowing a chiral smectic phase at a relatively wide range oftemperature, there still have been some problems in its stability.

Therefore, the present invention has an object of offering a new liquidcrystal which has good stability, and is highly likely to provide achiral smectic liquid crystal compound at a wide range of roomtemperature including room temperature.

DISCLOSURE OF THE INVENTION

Therefore, the present invention is a liquid crystal compound shown inthe following formula; ##STR6## wherein A and B respectively representsone of --O--, ##STR7## ;a and b are each 0 or 1; one of R₁ and R₂represents a normal chain alkyl group and the other represents an alkylgroup having an asymmetric carbon atom or for an alkoxyalkyl grouphaving an asymmetric carbon atom one of the groups --CH₃, --CN, --Cl isattached to the asymmetric carbon atom.

It is clear that many of the liquid crystal compounds shown in the aboveformula show the Sm C* phase at a wide temperature range including roomtemperature, and the response speed is very fast. It is understood thatthe response speed of this series of liquid crystal compounds is fasterthan the compound shown in the general formula; ##STR8##

It is thought that, though the framework portion of the molecule is asshort as the benzene ring and the pyrimidine ring which is directlybonded thereto the fact that the pyrimidine series liquid crystalcompounds of the present invention shows a high smectic characteristic,and that they show the Sm C* phase at a wide temperature range, isbecause the polarization of the molecule axis direction, caused by thedifference between the electric negativity of the pyrimidine ring andbenzene ring, and mutual function between the molecules, are large.Also, the reason for having a high-response ability is considered to bethe following: as the width of pyrimidine ring is wider than the widthof benzene ring, the molecule form is inflated in the center portion,and this inflated part acts to separate the distance between themolecules, the rotation viscosity of the molecule becomes small, andthus the speed of the response becomes faster.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a typical diagram of the smectic C* or H phase,

FIG. 2 is a typical drawing showing the movement of a chiral smecticphase liquid crystal molecule moving along the cone by an electricfield,

FIG. 3 is a graph showing the temperature dependance of the responsespeed,

FIGS. 4 to 8 are the graphs showing the variation of response speed whenn of 8 to 12 is fixed and m is variously changed.

BEST MODE OF CARRYING OUT THE INVENTION

The liquid crystal compound of the present invention is synthesized asfollows; ##STR9## wherein: X represents a lower alkyldiamine group,hydroxyl group or lower alkoxy group.

This reaction is carried out by selecting an appropriate solvent, and byutilizing an alkali metal alcoholate, such as alkali metal sodiumalcoholate, potassium t-butoxide, and and an anhydrous alkali metalsalt, such as anhydrous sodium carbonate or anhydrous potassiumcarbonate. As the solvent utilized in this reaction, the followingsolvents are appropriate; alcohol such as methanol, ethanol, propanol,isopropanol, butanol, or glycols; benzene, toluene, dimethyl formamide,dimethyl sulfoxide, tetrahydrofuran, ethylene glycol dimethyl ether anddiethylene glycol monomethyl ether. The reaction is carried out at roomtemperature, or at the reflux temperature of the solvent. ##STR10##

The first reaction is carried out by combining an alkali metalalcoholate and anhydrous alkali metal salt; in the second reaction,thionyl chloride, phosphorous trichloride, phosphorous pentachloride andphosphorous trichloride can be utilized other than oxy-phosphorouschloride, and N,N-diethylaniline can be replaced with a tertiary aminesuch as pyridine or triethylamine. Also the third reaction is adehalogenation by the contact reduction reaction.

Here, ##STR11## is synthesized as follows; ##STR12## X in the aboveformula (a) stands for the tolylsulfonyloxy group, methyloxy group or ahalogen atom; Y in the above formula (b) stands for an halogen atom oran active ester.

The reaction of formula (a) is conducted with an appropriate solventsuch as N,N-dimethylformamide, dimethyl sulfoxide, toluene, xylene,dioxane, and the condensation reaction is carried out by utilizingalkali metal or alkali metal hydride.

Also, in the above reaction (b), solvents of ether series such as ethylthe ether, tetrahydrofuran; aromatic series such as benzene, toluene;the ester series such as ethyl acetate and butyl acetate; and thehaloalkane series such as chloroform can be utilized, and a tertiaryamine such as pyridine, triethylamine, dimethylaniline, dimethylaminopyridine can be used as catalyst, to conduct the reaction smoothly.

Here, ##STR13## can be synthesized as follows; ##STR14##

Methods to synthesize phenyl pyrimidine holding various side chains areshown above, but now we will show methods to synthesize optically activeside chains.

Optically active alcohol is synthesized as follows;

Utilizing active amyl alcohol ##STR15## (neat)) as starting material, areaction is carried out to increase the number of carbon atoms by thealkyl malonic acid synthetic method so as to obtain, ##STR16##

The optically active alcohol thus made, can be changed to an aliphaticor aromatic compound, sulfonic acid ester, or halogenide, with the usualmethods.

With this method, the asymmetric carbon atom becomes the third carbonatom counting from the edge of side chain, and, the general syntheticmethod for preparing optically active side chains in which an asymmetriccarbon atom is positioned in another place, is as follows; ##STR17## inthe above formula, m+n is an integral number from 1 to 16, m=0 to 13,n=1 to 14, and * stands for asymmetric carbon atom

To obtain the chemical compound shown in formula (1),

Grignard reagent

    CH.sub.3 (CH.sub.2) m MgX                                  (2)

, where X represents a halogen atom, is made with an available alkylhalogenide and magnesium metal. While either a halide or an availableoptically active β-hydroxyisobutyric acid ester, by means of a methodusually utilizing 47% hydrobromic acid-sulfuric acid, or by carrying outa sulfonyl ester reaction on the acetate with a reaction between alkyl(or allyl) sulfonyl halide, is changed into a compound as shown informula (3). ##STR18## in the formula, Y stands for a halogen atom,p-toluen sulfonyloxy group, methanesulfonyloxy group, and * representsan asymmetric carbon atom.

Next, a coupling reaction onto the compound shown in formula (2) iscarried out and the compound shown in formula (3) in the presence of acatalyst such as a metal halide, for example, primary copper iodide,primary copper bromide, or secondary iron chloride, to obtain thecompound shown in formula (4). ##STR19## In the formula, m stands for anintegral number 0 to 13, R stands for a lower alkyl group such asmethyl, ethyl, propyl, and * stands for an asymmetric carbon atom

The compound obtained in the reaction shown in formula (4) is changedinto the alcohol shown in formula (1), by reducing with lithium aluminumhydride.

In the obtained compound (1), wherein m stands for an integral number 0to 13, n stands for 1, and * stands for an assymmetric carbon atom, thehydroxy group is changed into a halogen, methanesulfonyloxy group, orp-toluenesulfonyloxy group, by the usual halogenide reaction or by asulfonyl esterification reaction.

The compounds obtained with the above methods lead to compounds withdifferently positioned asymmetric carbon atoms, by appropriatelyselecting and conducting the usual reaction for increasing the number ofcarbon atoms for example, reduction after a malonic ester synthsis, thereduction and hydrolysis, after adding a cyano group and reduction toform a carboxylic acid after a Grignard reaction.

Thereby, the optically active alkanol compound shown in formula (1)having one asymmetric carbon atom at an arbitrary position within thealkyl chain is obtained.

The obtained compound shown in formula (1) is utilized as a side chainmaterial compound, either as it is, or by halogenizing or sulfonylesterizing the hydroxyl group.

Because the liquid crystal compounds offered in the present inventionhold one asymmetric carbon, there exists one pair of optical antipodes.These antipodes are included in the object compounds of the presentinvention, the optical characteristics of which are determined in thecompounds shown in formula (1), by selecting which antipode to use.

An explanation of the present invention referring to the examples is asfollows.

EXAMPLE 1 Synthesis of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]pyrimidine

(1) Synthesis of optically active (s)-4-(6-methyl octyloxy)benzonitrile.

Add 5.75 g of 4-cyanophenol 10 g of 1 brom-6-methyl octane synthesizedof available active amyl alcohol, 6.67 g of anhydrous potassiumcarbonate, 30 ml of N,N-dimethyl formamide into 100 ml four-mouth flaskunder nitrogen atmosphere, allow to react for 8 hours at 110° C. Afterthe reaction, filter the insoluble matter, then extract ether. Theorganic layer is then washed with 5% NaOH, water and saturated saltwater, then dried and evaporated to remove the ether. Then when theobtained oily matter is refined, 11.4 g of optical(s)-4-(6-methyloctyloxy)benzonitrile is obtained.

    ______________________________________                                        ν .sub.max.sup.Film (cm.sup.-1)                                                       2230      δ .sub.TMS.sup.CDCl.sub.3 (ppm)6.92, dJ =                               9Hz,                                                                1605      2H, AromaticH                                                       1570      7.57, dJ = 9Hz,                                                     1115      2H, AromaticH                                                                 3.97, tJ = 6Hz                                                                2H, --CH.sub.2 --O--                                     ______________________________________                                    

(2) Synthesis of optically active (s)-4-(6-methyloctyloxy)benzamidinehydrochloric acid salt.

Add 10 g of optically active (s)-4-(6-methyloctyloxy)benzonitrile, 12.5ml dry ethanol, and 16 ml dry benzene into a 100 ml four-mouth flask.Agitating this mixture, bubble in dried hydrogen chloride gas attemperature below 3° C., then blow in at below 3° C. After it is left atroom temperature for 2 days, evaporate and remove the solvent to obtainimpure crystals.

Put the obtained rough crystal into a 300 ml four-mouth flask with 64 mlof dry ethanol, then slowly drip into the flask 30 ml of dry ethanolwhich includes 11.08 g ammonia, at room temperature. After dripping, itis left at room temperature for three days. This is then refined, and9.58 g of optical (s)-4-(6-methyloctyloxy)benzamidine hydrochloric acidsalt is obtained.

    ______________________________________                                        ν .sub.max.sup.nujol (cm.sup.-1)                                                         3060                                                                          1680                                                                          1655                                                                          1105                                                             ##STR20##                                                                    (D.sub.2 O exchange characteristic)                                           7.14, d J = 9Hz, 2H, Aromatic H                                               8.06, d J = 9Hz, 2H, Aromatic H                                               4.09, t J = 6Hz, 2H, OCH.sub.2                                                ______________________________________                                    

(3) Synthesis of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]-4,6-dihydroxy pyrimidine.

Pour 1.15 g sodium metal, and 33 ml dry methanol into 100 ml four-mouthflask; add 5 g of optically active (s)-4-(6-methyloctyloxy)benzamidinehydrochloric acid salt, then pour 4.55 g of diethyl n-octylmalonate intothis sodium methylate solution and then allow to react for 18 hoursunder heat and reflux conditions. After cooling, acidify the mixtureutilizing concentrated sulfuric acid, and extract the crystals. Theimpure crystals are purified, and then optically active 6.32 g of(s)-5-n-octyl-2-[4-(6methyloctyloxy)phenyl]-4,6-dihydroxy-pyrimidine isobtained.

    ______________________________________                                               ν .sub.max.sup.nujol (cm.sup.-1)                                                    2660                                                                          1664                                                                          1610                                                                          1110                                                          ______________________________________                                    

(4) Synthesis of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]-4,6-dichloro-pyrimidine.

Pour 6 g of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]-4,6-dihydroxy-pyrimidine,27 ml of oxyphosphorous chloride, and 4 ml of N,N-diethylaniline into a50 ml flask, then allow to react for 21 hours under heat and refluxconditions. After the reaction, evaporate and remove the over obtainedoxyphosphorus chloride, then pour into ice water. Then extract this withether, wash with alkali water solution, then wash again with water andsaturated salt water until it is neutral. After drying the organiclayer, evaporate and remove the ether; then impure product is obtained.When this product is refined, 3.6 g of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]-4,6-dichloro-pyrimidine isobtained.

    ______________________________________                                        ν .sub.max.sup.nujol (cm.sup.-1)                                                         1610                                                                          1122                                                                          1090                                                            δ .sub.TMS.sup.CDCl.sbsp.3 (ppm)                                                      8.22, d J = 9Hz, 2H, Aromatic H                                               6.85, d J = 9Hz, 2H, Aromatic H                                               3.94, t J = 6Hz, 2H, CH.sub.2O                                                 ##STR21##                                                      ______________________________________                                    

(5) Synthesis of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]-pyrimidine.

Pour 1.88 g of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]-4,6-dichloro-pyrimidine,0.4 g of 10% palladium-carbon, 0.55 g of magnesium oxide, 60 ml ofethanol, and 45 ml of water, into a 200 ml flask, then add hydrogenunder oil bath conditions at 50° C., until the logical amount ofhydrogen has been absorbed. The catalyst is filtered and separated, thenether is extracted. After the ether layer is washed with water and withsaturated salt water, and dried, the ether is evaporated. The resultantimpure product is repeatedly refined, and 0.9 g of optically active(s)-5-n-octyl-2-[4-(6-methyloctyloxy)phenyl]-pyrimidine is obtained.

    ______________________________________                                        ν .sub.max.sup.nujol (cm.sup.-1)                                                         1610                                                                          1584                                                                          1110                                                             δ .sub.TMS.sup.CDCl.sbsp.3 (ppm)                                                      ##STR22##                                                                    8.35, d J = 9Hz, 2H, Aromatic                                                 6.94, d J = 9Hz, 2H, Aromatic                                                 3.99, t J = 6Hz, 2H, CH.sub.2O                                                 ##STR23##                                                      ______________________________________                                    

This liquid crystal compound showed a transmitting temperature asfollows: ##STR24##

To show a Sm C* phase at a wide temperature range including roomtemperature for a range of about 35 degrees (°C.), and also to hold a SmB phase under the Sm C* phase, the smectic domain condition is keptuntil 3° C. at the low temperature side. The Sm B phase does not respondto display, but because there is no distruction of the smectic domaincondition by crystallization, when at high temperature, and is turnedback to the Sm C* phase, the same display condition is turned ON/OFF, sothat the Sm B phase may be utilized for preservation under lowtemperature of LC panel time.

This liquid crystal compound is sandwiched between PVA rubbing one-axisorientation processed plates, and the liquid crystal layer fixed at athickness of 2.5 μm, with ±20 V voltage applied, under orthogonal nicol,the characteristics are then determined, with the following results;

the measuring temperature is 25° C.

the cone angle 40.5° C.

contrast (T on/T off) 12.5

response speed 600μ sec.

The temperature depending data of the response of this cell is shown inFIG. 3.

EXAMPLES 2 TO 31 General Formula

In the following formula: ##STR25## compounds with varying values of mand n are synthesized by the same method as Example 1.

The data of the transmitting temperature and the response speed measuredwith the same method as in example 1, is shown in Table 1.

FIGS. 4 to 8 are drawings showing the Sm C* temperature range andresponse speed of above compounds of Table 1, drawn in relation to thenumber of carbon atoms in the side chain.

                                      TABLE 1                                     __________________________________________________________________________    example                                      response                         No.  m n phase transition temperature        speed μsec                    __________________________________________________________________________     2   1 11                                                                               ##STR26##                           (28.3° C.)260             3   2  6                                                                               ##STR27##                           --                               4   2  7                                                                               ##STR28##                           --                               5   2  8                                                                               ##STR29##                           --                               6   2  9                                                                               ##STR30##                           (30° C.)380               7   2 10                                                                               ##STR31##                           (33° C.)610               8   2 11                                                                               ##STR32##                           (39° C.)530               9   2 12                                                                               ##STR33##                           (34° C.)540              10   3  6                                                                               ##STR34##                           --                              11   3  7                                                                               ##STR35##                          290                              12   3   8                                                                              ##STR36##                          250                              13   3  9                                                                               ##STR37##                          530                              14   3 10                                                                               ##STR38##                          330                              15   3 11                                                                               ##STR39##                           (27.4° C.)380            16   3 12                                                                               ##STR40##                          360                              17   3 14                                                                               ##STR41##                           (37.2° C.)450            18   4  6                                                                               ##STR42##                           --                              19   4  7                                                                               ##STR43##                           --                              20   4  8                                                                               ##STR44##                           (30° C.)260              21   4  9                                                                               ##STR45##                           (35° C.)430              22   4 10                                                                               ##STR46##                           (30° C.)600              23   4 11                                                                               ##STR47##                           (30° C.)530              24   4 12                                                                               ##STR48##                           (27° C.)620              25   5  6                                                                               ##STR49##                           (17° C.)810              26   5  7                                                                               ##STR50##                           (31° C.)250              27   5  9                                                                               ##STR51##                           (31° C.)700              28   5 10                                                                               ##STR52##                           (42° C.)1600             29   5 11                                                                               ##STR53##                           (31.5° C.)1100           30   5 12                                                                               ##STR54##                           (45° C.)1200             31   5 14                                                                               ##STR55##                           (66° C.)1700             __________________________________________________________________________

EXAMPLE 32 ##STR56## m=4, n=8, *=asymmetric carbon.

The method of synthesis of optically active(s)-5-octyl-2-[4-(6-methyloctanoneoxy)phenyl]pyrimidine is as follows.

Pour 1.78 g (62 mmol) 4-(5-octyl-2-pyrimidine)phenol and 15 ml of drypyrimidine into a 50 ml flask. Next, slowly drip 1.10 g (6.2 mmol) ofoptically active (s)-6-methyloctonic acid chloride into the flask withcooling under ice. After dripping, allow the reaction to continue forone whole day, returning the temperature to room temperature. After thereaction, pour it into ice water, then extract the product with ethylacetate. The organic layer is successively washed with water, NH₄ Cl, 5%NaOH, then washed again with water and saturated salt water until itbecomes neutral, then dried and the solvent is filtered and removed. Theobtained impure product is repeatedly refined, and5-n-octyl-2-[4-(6-methyloctanoneoxy)phenyl]pyrimidine 1.5 g (57%) isobtained.

    ______________________________________                                        I.R. (nujol): ν = 1762.1588 cm.sup.-1                                      .sup.1 HN.M.R. (60MHz, CDCl.sub.3 /TMSint)                                    δ(ppm) = 8.62 (S,2H,Pyrimidine H)                                       8.48 (d,2H,J = 9Hz,Aromatic H)                                                7.12 (d,2H,J = 9Hz,Aromatic H)                                                 ##STR57##                                                                    ______________________________________                                    

The transformation temperature of this liquid crystal compound is asfollows. ##STR58##

This liquid crystal compound is sandwiched between PVA rubbing one-axisorientation processed plates, and the liquid crystal layer is fixed at athickness of 2.5 μm, ±20 V voltage applied, then measured thecharacteristic under orthogonal nicol condition. The measuringtemperature was 35° C.

Contrast (T on/T off): 11.5

Response speed: 3 ms

EXAMPLES 33 TO 38

The object compounds were obtained by means of operations similar toExample 1, utilizing the below mentioned optically active alkyl acidhalide and alkyl pyrimidine phenol, as follows.

    TABLE 2      starting material object compound       m      ##STR59##      n      ##STR60##      yield (%)      ##STR61##               2      ##STR62##      8     ##STR63##      69 m = 2n = 8 17601585 8.56 (S,2H,Pyrimidine H)8.45 (d,2H,Aromatic     H)7.18 (d,2H,Aromatic H)2.37˜2.88 (m,4H,CH.sub.2CO,CH.sub.2Pyrimidi     ne)      0     ##STR64##      11      ##STR65##      67 m = 0n =      11 17581585     ##STR66##      2     ##STR67##      11      ##STR68##      65 m = 2n = 11 17601585 8.56 (S,2H,Pyrimidine H)8.42 (d,2H,Aromatic     H)7.16 (d,2H,Aromatic H)2.40˜2.85 (m,4H,CH.sub.2CO,CH.sub.2Pyrimidi     ne)      4     ##STR69##      11      ##STR70##      89 m = 4n = 11 17551590 8.62 (S,2H,Pyrimidine H)8.48 (d,2H,Aromatic     H)7.22 (d,2H,Aromatic H)2.35˜2.90 (m,4H,CH.sub.2CO,CH.sub.2Pyrimidi     ne)      2     ##STR71##      14      ##STR72##      51 m = 2n = 14 17581584 8.57 (S,2H,Pyrimidine H)8.45 (d,2H,Aromatic     H)7.17 (d,2H,Aromatic H)2.35˜2.80 (m,4H,CH.sub.2CO,CH.sub.2Pyrimidi     ne)  4 CH.sub.3 CH.sub.2 CH(CH.sub.2).sub.4      COCl 14     ##STR73##      61 m = 4n = 14 17551584 8.57 (S,2H,Pyrimidine H)8.42 (d,2H,Aromatic     H)7.12 (d,2H,Aromatic H)2.30˜2.72 (m,4H,CH.sub.2      CO,CH.sub.2Pyrimidine)

The transition temperature and the response speed of these liquidcrystals, measured in the similar way to example 1 is shown in thefollowing table.

    __________________________________________________________________________     ##STR74##                                                                                                      response speed                              m n transition temperature (°C.)                                                                         (measured temperature)                      __________________________________________________________________________    2  8                                                                               ##STR75##                    --                                          0 11                                                                               ##STR76##                    --                                          2 11                                                                               ##STR77##                    28.5 μs (32.0° C.)                4 11                                                                               ##STR78##                    350 μs (56.7 °C.)                 2 14                                                                               ##STR79##                    350 μs (36.7°C.)                  4 14                                                                               ##STR80##                    260 μs (50.2° C.)                 __________________________________________________________________________

Here, Sm X and SmY stand for the Smectic phases except for the Sm Aphase and the Sm C* phase; because it is not specifiable, we noted it asSm X, Sm Y. * stands for supercooling.

As shown in the above table, with a liquid crystal of m=2, n=8, and aliquid crystal wherein m=0, n=11, the response speed cannot be measuredbecause they do not have a Sm C* phase, but from various blendexperiments, it has been determined that they can be utilized as anadditive to speed up the response speed.

EXAMPLE 39 ##STR81##

(1) Synthesis of(s)-5-n-octyl-2-[4-(1-hydroxy-6-methyloctanoyl)phenyl]pyrimidine.

Combine 0.82 g of (s)-4-(1-hydroxy-6-methyloctyl)benzamidinehydrochloric acid salt, and 0.56 g of β-n-octyl-α-dimethylaminoacrolein, after resolving in 20 ml dry ethanol, add 2.04 g 28% sodiummethylate methanol solution, and allow the reaction to proceed for 13hours under reflux. After the reaction, pour it into ice water and addhydrochloric acid, and then extract the reaction product with ethylacetate. The ethyl acetate layer is washed with water and saturated saltwater, dried, then filtered and the solvent removed. The obtained impureproduct is refined with silica gel chromatography and recrystallization,then optically active(s)-5-n-octyl-2-[4-(1-hydroxy-6-methyloctanoyl)phenyl]pyrimidine 0.64 gis obtained.

    ______________________________________                                        IR ν max cm.sup.-1 :                                                                           3260, 1595, 1555                                                              1440, 800                                                 .sup.1 H--NMR (60MHz, CDCl.sub.3)                                             δ (ppm):      8.67 (S, 2H)                                                                  8.45 (d, 2H)                                                                  7.50 (d, 2H)                                                                  4.77 (t, 1H)                                                                  2.2˜2.8 (m,)                                        ______________________________________                                    

(2) Synthesis of (s)-5-n-octyl-2-[4-(6-methyloctanoyl)phenyl]pyrimidine.

Combine 0.107 g of pyrimidinium bichromate with 5 ml of driedN,N-dimethylformamide. Next, slowly drip 0.08 g of(s)-5-n-octyl-2-[4-(1-hydroxy-6-methyloctyl)phenyl]pyrimidine dissolvedin 2 ml dried N,N-dimethylformamide 2 ml at room temperature.

When the dripping finishes, the reaction is allowed to continue for 2hours at room temperature. After the reaction, add ether, to dilute it,then filter and separate the unsoluble matter, utilizing ahigh-flow-super-cell, the conduct an ether extraction of the reactedproduct. The ether layer is washed with dilute hydrochloric acid andwater, dried filtered and the solvent removed. The resultant impureproduct is purified by silica gel chromatography and recrystallization,and 0.028 g of (s)-5-n-octyl-2-[4-(6-methyloctanoyl)phenyl]pyrimidine isobtained.

    ______________________________________                                        IR ν max cm.sup.-1 : 1680, 1610, 1580, 1545                                .sup.1 H--NMR (60MHz, CDCl.sub.3)                                             δ (ppm):                                                                           0.6˜2.2    (m, 30H)                                                     2.64             (t, 2H)                                                      3.01             (d, 2H)                                                      8.07             (d, 2H)                                                      8.55             (d, 2H)                                                      8.66             (S, 2H)                                           ______________________________________                                    

The phase transition temperature of this liquid crystal compound is asfollows; ##STR82##

Furthermore, this liquid crystal compound is sandwiched between PVArubbing one-axis orientation processed plates, the liquid crystal layeris fixed at a thickness of 2.5 μm, ±20 V voltage applied, and theresponse at orthogonal nicol measured, with the result that the valuebecame 200 us, at 61° C.

EXAMPLE 40 ##STR83## Synthesis of optically active(s)-5-n-octyl-2-[4-(3'chloropentyloxy)phenyl]pyrimidine

Pour 0.77 g of sodium hydride (about 50% oil suspension) and 3 ml of dryN,N-dimethyl formamide into 10 ml two-mouth flask equipped with adripping funnel, cooling tube and calcium chloride tube. Then drip 0.38g of 4-(5-n-octyl-2-pyrimidinyl)phenol dissolved in 1 ml of dryN,N-dimethylformamide, into the flask at a temperature below thefreezing point. After reaction for 30 minutes at room temperature, drip0.37 g of optically active (s)-3-chloropentyl p-toluenesulfonic acidester; this compound was synthesized by the general method withL(+)-3-hydroxyvaleric acid methyl ester [[α]_(D) ²⁰ =+28.1, (C=1,CHCl₃)] which is dissolved into 1 ml dry N,N-dimethylformamide.

When the dripping finishes, the reaction is allowed to continue for 8hours using an 100° C. at oil bath. After the reaction, dry it, pour itinto ice water, and extract it with ethyl acetate. The ethyl acetatelayer is washed with 5% NaOH and water, dried, and the organic solventfiltered, and removed. The remaining oil-like is purified by means of asilica gel column chromatography, and repeatedly refined byrecrystallization; 0.19 g of optically active(s)-5-n-octyl-2-[4-(3'-chloropentyloxy)phenyl]pyrimidine is obtained.

    ______________________________________                                        IR ν.sup.film .sub.max (cm.sup.-1)                                                     1610, 1585, 1430, 1250, - 1170, 1110, 800, 750                    .sup.1 H--NMR (60MHz, CDCl.sub.3 /TMS int)                                    δ (ppm):                                                                            8.62        (S, 2H, Pyrimidine H)                                             8.42        (d, 2H, Aromatic H)                                               7.02        (d, 2H, Aromatic H)                                               4.03        (t, 2H, --CH.sub.2 --O--)                                         2.60        (t, 2H, --CH.sub.2 --pyr)                             ______________________________________                                    

The transition temperature! ##STR84## (here, * shows supercooling)

The compound of this example ##STR85## does not have the Sm C* phase, sowe measured the transition temperature and the response speed of theliquid crystal compound obtained by blending the above compound and thecompound of Example 1. ##STR86## in a proportion of 1:3.

The transition temperatures: ##STR87##

The response speed: 220 μs (25° C.)

As it is obvious from comparison with the data of Example 1, the liquidcrystal compound of this example has a faster response speed.

EXAMPLE 41 ##STR88## Synthesis of optically active(s)-5-n-undecyl-2-[4-(3'-cyanopentyloxy-phenyl]pyrimidine

(1) Method of synthesis of optically active(s)-5-n-undecyl-2-[4-(3'-methanesulfonyloxy-pentyloxy)phenyl]pyrimidine.

Dissolve 2.5 g of optically active(s)-5-n-undecyl-2-[4-(3'-hydroxy-pentyloxy)phenyl]pyrimidine in 25 mldry pyridine. Slowly drip 0.76 g of methanesulfonyl chloride into thissolution at -5° C. when dripping is complete, the reaction is continuedfor 2 more hours, dried, then allowed to react for another 2 hours atroom temperature. After the reaction, pour it into ice water, andextract with ether. The ether layer is washed with dilute hydrochloricacid and water, dried and evaporated to remove the ether; an oil-likeproduct is obtained. The oil-like product is crystallized and separated,and 2.63 g of optically active(s)-5-n-undecyl-2-[4-(3'-methanesulfonyloxypentyloxy)phenyl]pyrimidineis obtained.

    ______________________________________                                        I.R. ν .sub.max.sup.nujol (cm.sup.-1):                                                       1610, 1590, 1435, 1337,                                                       1183, 1173, 910, 800                                        ______________________________________                                    

(2) Method of synthesis of optically active(s)-5-n-undecyl-2-[4-(3'-cyanopentyloxy)phenyl]pyrimidine.

Pour 2.63 g of optically active(s)-5-n-undecyl-2-[4-(3'-methanesulfonyloxy-pentyloxy)phenyl]pyrimidineobtained by means of method (1), and 10 ml of dry dimethyl sulfoxideinto a 30 ml flask equipped with a cooling tube and calcium chloridetube, then after it is dissolved, add 0.32 g of sodium cyanide into it,and agitate it for 15 hours at 80° to 90° C., leave it to cool down,pour it into ice water, then ether extract to the reaction matter. Theether layer is washed with dilute hydrochloric acid and water, dried,the ether is evaporated and removed, and oil-like matter is obtained.This oil-like matter is crystallized and separated, and then 2.63 g ofoptically active(s)-5-n-undecyl-2-[4-(3'-methanesulfonyloxypentyloxy-pentyloxy)phenyl]pyrimidine is obtained.

The specific rotatory power is [α]_(D) ²⁵ =-28.57° C. (C=2, CHCl₃), butthe optical purity has not been studied enough.

    ______________________________________                                        I.R ν .sub.max.sup.nujol (cm.sup.-1):                                                       2240, 1605, 1585, 1430,                                                       1245, 1165, 797                                              .sup.1 H--NMR (60MHz, CDCl.sub.3 /TMS int)                                    δ (ppm):   8.60 (S, 2H, Pyrimidine H)                                                    8.40 (d, 2H, Aromatic H)                                                      7.00 (d, 2H, Aromatic H)                                                      4.20 (t, 2H, --CH.sub.2 --O--)                                                0.65˜3.15 (m, 31H)                                     ______________________________________                                    

We measured the transition temperature of the obtained compound, and weobtained the following result.

The transition temperature: ##STR89## (wherein * shows supercooling).

As the compound of this example ##STR90## does not have the Sm C* phase,we measured the transition temperature and the response speed of theliquid crystal compound obtained by blending the above compound with thecompound of Example 1 ##STR91## at a portion of 1:3.

The transition temperature: ##STR92##

The response speed: 180 μs (30.0° C.).

As obvious from the comparison with the data of Example 1, it isunderstood that the liquid crystal compound of this example has a fasterresponse speed without greatly changing the transition temperature.

EXAMPLE 42 ##STR93##

(1) Method of synthesis of optically active (s)-alkoxy alcohol (commonto all the examples)

By having active amyl alcohol ([α]_(D) ²⁵ =-4.48° (neat)) as startingmaterial and by reacting with appropriate diole in the general method,the following composition can be obtained. ##STR94##

The optically active alkoxy alcohol obtained as above, can easily bechanged to an alphatic or aromatic sulfonic acid ester or into to ahalide.

(2) Method of synthesis of optically active(s)-5-n-hexyl-2-[4-(2-methylbutyloxy]phenyl]pyrimidine.

Pour 16 ml of dry N,N-dimethyl formamide and 0.29 g of sodium hydride(about 50% oil suspension), into a 100 ml four-mouth flask equipped withcooling tube, dropping funnel, thermometer, and calcium chloride tube.Next, drip 1.61 g of 4-(5-n-hexyl-2-pyrimidinyl)phenol dissolved in 4 mlof dry N,N-dimethylformamide, allow it react until the hydrogen stopsgenerating, then drip 2.0 g of optically active (s)-p-toluenesulfonicacid 2-methylbutyloxybutyl ester (this compound is obtained from theactive amyl alcohol obtained according to the above method (1)) into themixture and react for 7 hours at 70° to 80° C. After the reaction, it ispoured into ice water, and the product is extracted with chloroform.

The chloroform layer is water-washed and dried, and the chloroform isevaporated and removed. The obtained impure product is repeatedlyrefined, and 1.2 g of optically active(s)-5-n-hexyl-2-[4-(2'-methylbutyloxybutyloxy).phenyl]pyrimidine isobtained.

    ______________________________________                                        I.R. ν .sub.max.sup.film(cm.sup.-1):                                                       1610, 1585, 1425, 1250,                                                       1170, 1110, 800                                               .sup.1 HNMR (60 MHz,                                                                          8.52 (S, 2H, Pyrimidine H)                                    CDCl.sub.3 /TMS int) δ (ppm):                                                           8.36 (d, 2H, Aromatic H)                                                      6.94 (d, 2H, Aromatic H)                                                       ##STR95##                                                                     ##STR96##                                                                     ##STR97##                                                                    2.50 (t, 2H, CH.sub.2pyr)                                                     0.5˜2.2 (m, 24H)                                        ______________________________________                                    

The following result were obtained by measuring the transitiontemperature (0° C.) of this compound. ##STR98##

EXAMPLE 43

We synthesized optically active(s)-5-n-octyl-2-[4-(2'-methylbutyloxybutyloxy)phenyl]pyrimidine with amethod similar to that of Example 42.

    ______________________________________                                         ##STR99##                                                                    I.R. ν.sup.film .sub.max = :1610, 1585, 1430, 1250, 1170, 1110, 800        .sup.1 HNMR (60MHz, CDCl.sub.3 /TMS int)                                      δ(ppm): 8.50 (S, 2H, Pyrimidine H)                                      8.40 (d, 2H, Aromatic H)                                                      6.99 (d, 2H, Aromatic H)                                                       ##STR100##                                                                    ##STR101##                                                                    ##STR102##                                                                    ##STR103##                                                                   0.5˜2.1 (m, 28H)                                                        ______________________________________                                    

The following results were obtained by measuring the transitiontemperature (°C.) of the obtained compound. ##STR104##

EXAMPLE 44

We synthesized optically active(s)-5-n-undecyl-2-[4-(2'-methylbutyloxybutyloxy)phenyl]pyrimidine with amethod similar to that of Example 42.

    ______________________________________                                         ##STR105##                                                                   I.R. ν.sup.film .sub.max = :1610, 1585, 1435, 1260, 1175, 1115, 800        .sup.1 HNMR (60MHz, CDCl.sub.3 /TMS int)                                      δ(ppm): 8.57 (S, 2H, Pyrimidine H)                                      8.36 (d, 2H, Aromatic H)                                                      6.98 (d, 2H, Aromatic H)                                                       ##STR106##                                                                    ##STR107##                                                                   3.20 (dd, 2H, CHCH.sub.2O)                                                    2.55 (t, 2H, CH.sub.2pyr)                                                     0.5˜2.1 (m, 34H)                                                        ______________________________________                                    

The following results were obtained by measuring the transitiontemperature (°C.) of this compound. ##STR108##

EXAMPLE 45 ##STR109## Method of synthesis of optically active(s)-2-[4-n-octyloxyphenyl]-5-[6-methyloctyl]pyrimidine

Pour 0.33 g of sodium hydride (about 50% oil suspension), 3 ml of dryN,N-dimethylformamide into a 30 ml three-mouth flask equipped with acooling tube, thermometer, dripping funnel, and calcium chloride tube.Next, slowly drip 1.71 g of optically active (s)-4-[5-(6-methyloctyl)-2-pyrimidinyl]phenol which is dissolved in 6 ml of dryN,N-dimethylformamide, into the flask at room temperature. Furthermore,after reacting it for 30 minutes, add 1.10 g of 1-bromoctane, allow toreact for 7 hours at 90° C. After the reaction, pour the mixture intoice water, then extract the product with ethyl acetate. The organiclayer is thoroughly washed with water, dried, the organic solvent isevaporated and removed, and then the impure product is obtained. Thisimpure product is refined with silica gel chromatography, andrecrystallized to obtain 1.3 g of optically active(s)-2-[4-n-octyloxyphenyl]-5-[6-methyloctyl]pyrimidine.

    ______________________________________                                        I.R ν max (cm.sup.-1): 1610, 1585, 1430, 1250 1170, 800                    .sup.1 HNMR (60MHz, CDCl.sub.3)                                               δ(ppm): 8.38 (S, 2H)                                                    8.28 (d, 2H)                                                                  6.97 (d, 2H)                                                                  3.27˜4.20 (m, 4H)                                                       0.6˜2.1 (m, 32H)                                                         ##STR110##                                                                   ______________________________________                                    

EXAMPLE 46 Method of synthesis of(s)-2-(4-n-octylphenyl)-5-(6-methyloctyloxy)pyrimidine

Pour 2.64 g of 4-n-octylbenzamidine hydrochloric acid salt, 2.38 g of(s)-α-(6-methyl octyloxy)-β-(dimethylamino)acrolein, and 20 ml ethanolanhydride into a three-mouth flask equipped with a cooling tube, calciumchloride tube, dripping funnel, and thermometer. Next, slowly drip 4.18g of 28% sodium methylate.methanol solution into the flask, at roomtemperature. After the dripping, and refluxing, we examined the reactionfor 11 hours. When the reaction finishes, pour it into ice water, andextract the reaction product with ethyl acetate. The ethyl acetate layeris water washed, dried, and the solvent is evaporated and removed at lowpressure. The obtained impure product is refined with silica gel columnchromatography, and recrystallized, and then 2.41 g of(s)-2-[4-n-octylphenyl)-5-(6-methyloctyloxy)pyrimidine is obtained.

    __________________________________________________________________________    I.R νmax (cm.sup.-1): 1610, 1578, 1440 1280, 785                           .sup.1 HNMR (60MHz, CDCl.sub.3)                                               δ(ppm): 0.65˜2.2 (m, 32H)                                         2.66 (t, 2H)                                                                  4.04 (t, 2H)                                                                  7.30 (d, 2H)                                                                  8.30 (d, 2H)                                                                  8.45 (s, 2H)                                                                   ##STR111##                                                                   __________________________________________________________________________

Here, Sm X and Sm Y are smectic phases, which phases are unconfirmed.

EXAMPLE 47 ##STR112## Method of synthesis of(s)-5-(n-undecyloxy)-2-[4-(2-methylbutyloxy)phenyl]pyrimidine

Suspend 0.185 g of 50% sodium hydride in 2 ml of dry DMF, slowly drip1.1 g of 2-(4-hydroxyphenyl)-5-(n-undecyl)pyrimidine which is resolvedin 5 ml of dry DMF at a temperature below freezing point into themixture, agitate for 30 minutes at room temperature, and then drip 0.785g of 2-methyl-1-(p-trisulfonoxy)-butane (this is regulated by (s)-amylalcohol ([α]_(D) ²³ -5.8° (neat)). Next, after agitating the reactionsolution for 5 hours at 100° C., pour it into ice water, and extract thereaction product with ethyl acetate.

The ethyl acetate layer is washed with 5% NaOH, dried with magnesiumsulfate, the remaining sediment is purified by evaporating and removingthe solvent, with silica gel column chromatography and recrystallizationto obtain(s)-5-n-(n-undecyloxy)-2-[4-(2-methylbutyloxy)phenyl]pyrimidine, atyield of 76%.

EXAMPLE 48 TO 50

With the compound shown in the following general formula, we synthesizeda compound where we changed m and n by a method similar to that ofExample 47. ##STR113## The characteristics of these compounds are allshown in the following table with Example 47.

                  TABLE 4                                                         ______________________________________                                        Characteristic values of the compounds                                        object                                                                        compound  IR τ max cm.sup.-1                                                                     .sup.1 H--NMR                                          ______________________________________                                        example 47                                                                              1615, 1590, 1550,                                                                          0.7˜2.2                                                                             (m, 30H)                                   m = 1     1525, 1445, 1250                                                                           3.85        (d, 2H)                                     n = 11                4.04        (t, 2H)                                                           7.00        (d, 2H)                                                           8.33        (d, 2H)                                                           8.42        (s, 2H)                                    example 48                                                                              1612, 1585, 1555,                                                                          0.7˜2.1                                                                             (m, 27H)                                   m = 2     1512, 1440   4.05        (t, 4H)                                     n = 8                 6.95        (d, 2H)                                                           8.28        (d, 2H)                                                           8.36        (s, 2H)                                    example 49                                                                              1610, 1584, 1525,                                                                          0.6˜2.1                                                                             (m, 32H)                                   m = 5     1515, 1435   2.60        (t, 2H)                                     n = 8                 4.00        (t, 2H)                                                           6.97        (d, 2H)                                                           8.36        (d, 2H)                                                           8.57        (s, 2H)                                    example 50                                                                              1610, 1510, 1550,                                                                          0.7˜2.27                                                                            (m, 32H)                                   m = 2     1512, 1440   4.13        (t, 4H)                                     n = 11                7.02        (d, 2H)                                                           8.35        (d, 2H)                                                           8.45        (s, 2H)                                    ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                        The phase transition temperature and the response speed                       of the compound                                                               object                          response                                      compound                                                                              transition temperature  speed                                         ______________________________________                                        example 47 m = 1 n = 11                                                                ##STR114##             τ = 290 μs (66° C.)             example 48 m = 2 n = 8                                                                 ##STR115##             τ = 900 μs (65° C.)             example 49 m = 5 n = 8                                                                 ##STR116##             τ = 1.5 ms (43° C.)                example 50 m = 2 n = 11                                                                ##STR117##             τ = 310 μs (70° C.)             ______________________________________                                         (here, *stands for supercooling)                                         

EXAMPLE 51 ##STR118##

We synthesized (s)-5-(n-octyloxy)-2-[4-(2-methyloctyl)phenyl]pyrimidineby means of a method similar to that of Example 47.

The response speed, determined by a method similar to that of thetransition temperature, is shown as follows.

Transition temperature: ##STR119##

Response speed: 300 μs (30° C.).

EXAMPLE 52 ##STR120## wherein n=11, * shows an asymmetric carbon atomand m, with reference to the general formula, is 0. Method of synthesisof (s)-5-n-undecyloxy-2-[4-(2-methylbutanoyloxy)phenyl]pyrimidine

Pour 0.328 g of 2-methylbutanoic acid synthesized from (s)-amylalcohol([α]_(D) ²³ -5.8° (neat)), 1.1 g of4-(5-n-undecyloxy-2-pyrimidinyl)phenol, 8 ml of anhydrous chloroform and0.662 g of 4-dimethylaminopyridine, S,S'-dicyclohexylcarbodimide into a25 ml flask and allow to react for one whole day at room temperature.After the reaction, filter and separate the insoluble matters, andextract the reaction product with chloroform. The organic layer iswashed with water, 2N hydrochloric acid and water, dried and evaporatedto remove the organic solvent. The reaction product is purified withsilica gel chromatography and re-crystallized crystal, and thenoptically active(s)-5-n-undecyloxy-2-[4-(2-methylbutanoyloxy)phenyl]pyrimidine isobtained at a yield of 70%.

    ______________________________________                                        I.R ν .sub.max.sup.nujol (cm.sup.-1):                                                          1762, 1602, 1550,                                                             1440, 1278,                                               .sup.1 H--NMR (60MHz, CDCl.sub.3)                                             δ (ppm):      8.42 (S, 2H)                                                                  8.40 (d, 2H)                                                                  7.17 (d, 2H)                                                                  4.40 (t, 2H)                                                                  2.3˜2.8 (m, 1H)                                                         0.6˜2.2 (m, 29H)                                    ______________________________________                                    

EXAMPLES 53 TO 57

We obtained the object compounds with a operation similar to Example 1,utilizing the (s) alkylcarboxylic acid synthesized from the belowmentioned (s) amyl alcohol[α]_(D) ⁻²³ -5.8° (neat), andalkyloxypyrimidinyphenol.

Refer to the following Table 6.

    TABLE 6      object compound         example     ##STR121##      ##STR122##                53 0      ##STR123##      8      ##STR124##      60 m = 0n = 8 176015551440129012051160 8.47 (S,2H)8.37 (d,2H)7.17       4     (d,2H).17 (t,2H)2.35˜3.04 (m,1H)0.77˜2.35 (m,23H)  54 1      ##STR125##      8      ##STR126##      77 m = 1n =      8 17621598156014501290 8.41 (S,2H)8.36 (d,2H)7.16 (d,2H)4.08 (t,2H)2.31.     about.2.85 (m,2H)0.7˜2.25 (m,24H)      55 2     ##STR127##      8      ##STR128##      66 m = 2n =      8 17621598156014501290 8.43 (S,2H)8.42 (d,2H)7.21 (d,2H)4.05 (t,2H)2.58     (t,2H)0.6˜2.1 (m,30H)      56 4     ##STR129##      8      ##STR130##      75 m = 4n = 8 176215981560 8.44 (S,2H)8.40 (d,2H)7.19 (d,2H)4.06     (t,2H)2.58 (t,2H)0.65˜2.15 (m,30H)      57 1     ##STR131##      11      ##STR132##      66 m = 1n =      11 17601598156014501290 8.42 (S,2H)8.35 (d,2H)7.27 (d,2H)4.08 (t,2H)2.32     ˜2.82 (m,2H)0.68˜2.27 (m,30H)

                                      TABLE 7                                     __________________________________________________________________________    The transition temperature and the response speed of the compounds            object                                                                        compound                                                                            phase transition temperature     response speed                         __________________________________________________________________________    example 52 m = 0 n = 11                                                              ##STR133##                      τ = 230 μs (60° C.)      example 53 m = 0 n = 8                                                               ##STR134##                      τ = 150 μs (62° C.)      example 54 m = 1 n = 8                                                               ##STR135##                      τ = 250 μs (66° C.)      example 55 m = 2 n = 8                                                               ##STR136##                      --                                     example 56 m = 4 n = 8                                                               ##STR137##                      τ = 1.3 ms (78° C.)         example 57 m = 1 n = 11                                                              ##STR138##                      τ = 240 μs (60°          __________________________________________________________________________                                           C.)                                     *shows supercooling                                                      

EXAMPLES 58 TO 61

The the structural formula and the transition temperature of synthesizedspecific compounds are shown in the following Table 8.

                                      TABLE 8                                     __________________________________________________________________________    example                                                                       No.  structural formula        phase transition temperature                   __________________________________________________________________________                                   (°C.)                                   58                                                                                  ##STR139##                                                                                              ##STR140##                                    59                                                                                  ##STR141##                                                                                              ##STR142##                                    60                                                                                  ##STR143##                                                                                              ##STR144##                                    61                                                                                  ##STR145##                                                                                              ##STR146##                                    __________________________________________________________________________

EXAMPLE 62 Method of synthesis of (R)-5-n-undecyl-2-[4-(2'-methylbutyloxy)phenyl]pyrimidine

Suspend 0.57 g of 50% sodium hydride in 6 ml of driedN,N-dimethylformamide, dissolve and add 3.2 g of2-(4-hydroxyphenyl)-5-n-undecylpyrimidine to 6 ml of dryN,N-dimethylformamide, agitate it for 60 minutes at room temperature,dissolve and add 2.9 g (R)-2-methyl-1-(p-toluensulfonyl)oxybutane to 5ml of dry N,N-dimethylformamide, heat the compound to 75° to 80° C.,allow to react under agitation for 8 hours, pour the reacted solutioninto ice water, extract with ethyl acetate, wash with salt water, drywith magnesium sulfate, evaporate and remove the solvent; 4.27 g ofsediment remains. Purify this with silica gel column chromatography andrecrystallization and 2.0 g of (R)-5-n-undecyl-2-[4-(2'-methylbutyloxy)phenyl]pyrimidine are obtained.

    ______________________________________                                        (α) .sub.D.sup.25 - 7.05 (C = 2.0, CHCl.sub.3)                          I.R ν max (cm.sup.-1):                                                                        1610, 1590, 1435, 1255,                                                       1170, 850, 800                                             .sup.1 H--NMR (60MHz, CDCl.sub.3)                                             δ (ppm):     0.6˜2.23 (m, 30H)                                                       2.53 (t, 2H)                                                                  3.72 (d, 2H)                                                                  6.88 (d, 2H)                                                                  8.24 (d, 2H)                                                                  8.43 (s, 2H)                                               ______________________________________                                    

The transition temperature of this liquid crystal compound is asfollows. ##STR147## * shows supercooling.

This liquid crystal compound is sandwiched between PVA rubbing one-axisorientation processed plates, the liquid crystal layer thickness fixedat 2.5 μm, ±20 voltage applied, and the characteristic measured atorthogonal nicol. The measuring temperature is 35° C.

The response speed: 210 μs.

EXAMPLE 63 Method of synthesis of(R)-5-n-octyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine

Suspend 0.605 g of 50% sodium hydride into 5 ml dryN,N-dimethylformamide, dissolve and add 3.0 g of2-(4-hydroxyphenyl)-5-n-octyl pyrimidine in 7 ml of dry dimethylformamide, agitate for 60 minutes at room temperature, dissolve and add2.84 g of (R)-4-methyl-1-(p-toluenesulfonyl).oxyhexane to 5 ml. of dryN,N-dimethylformamide, heat the compound to 75° to 80° C., reaction toproceed under agitation for 8 hours, pour into ice water, extract withethyl acetate, wash with salt water, dry with magnesium sulfate,evaporate and remove the solvent, and 4.15 g of sediment remains. Refinethis sediment with silica gel column chromatography andrecrystallization, and 2.5 g of (R)-5-n-octyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine are obtained.

    ______________________________________                                        (α) .sub.D.sup.25 - 5.25 (C = 2, CHCl.sub.3)                            I.R ν max (cm.sup.-1):                                                                      1610, 1590, 1435, 1255, 1170                                                  850, 802                                                     .sup.1 H--NMR (60MHz, CDCl.sub.3)                                             δ (ppm):   0.6˜2.20 (m, 28H)                                                       2.55 (t, 2H)                                                                  3.97 (t, 2H)                                                                  6.91 (d, 2H)                                                                  8.25 (d, 2H)                                                                  8.48 (s, 2H)                                                 ______________________________________                                    

The transition temperature of this liquid crystal compound is asfollows; ##STR148## * shows supercooling.

This liquid crystal compound is sandwiched between PVA rubbing one-axisorientation processed plates, the liquid crystal layer fixed at athickness of 2.5 μm, ±20 V of voltage applied, and the characteristicsmeasured under orthogonal nicol. The measured temperature is 27° C.

The response speed is 245 μs.

UTILIZATION POSSIBILITY IN INDUSTRY

As shown in the above examples, the new liquid crystal compounds of thepresent invention have a very good response ability, and are compoundswhich hold the Sm C* phase over a wide temperature range close to roomtemperature, thus, resulting in liquid crystal compounds having apractical Sm C* phase temperature range; these are highly advantageouscompositions which will contribute much to the practice of ferroelectricliquid crystal display.

We claim:
 1. A ferroelectric liquid crystal compound of the formula##STR149## wherein one of R₁ and R₂ is a straight chain alkyl group of 5to 14 carbon atoms and the other is an alkyl or alkoxyalkyl group whichcontains just one asymmetric carbon atom, each of a and b is 0 or 1, onemember of the group --CH₃, --CN or --Cl is attached to the asymmetriccarbon atom and each of A and B is --O--, ##STR150## wherein: when a is0, B is --O-- and b is 1;when A is --O-- and a is 1, B is --O-- or##STR151## and b is 0 or 1; when A is ##STR152## and a is 1, B is --O--and b is 0 or 1, and when A is ##STR153## and a is 1, b is
 0. 2. Aferroelectric liquid crystal compound as claimed in claim 1, of theformula ##STR154## wherein R₃ * is an alkyl group containing just oneassymmetric carbon atom and R₄ is a straight chain alkyl group.
 3. Aferroelectric liquid crystal compound as claimed in claim 1, of theformula ##STR155## wherein R₃ * is and alkyl group containing just oneasymmetric carbon atom and R₄ is a straight chain alkyl group.
 4. Aferroelectric liquid crystal compound as claimed in claim 1, of theformula ##STR156## wherein R₃ * is an alkyl group containing just oneasymmetric carbon atom and R₄ is a straight chain alkyl group.
 5. Aferroelectric liquid crystal compound as claimed in claim 1, of theformula ##STR157## wherein m is 0 to 8, n is 5 to 14, X is --Cl or --CNand * shows an asymmetric carbon atom.
 6. A ferroelectric liquid crystalcompound as claimed in claim 1, of the formula ##STR158## wherein m is 1to 8, n is 5 to 14 and C shows the assymetric carbon atom.
 7. Aferroelectric liquid crystal compound as claimed in claim 1, of theformula ##STR159## wherein R₃ * is an alkyl group containing just oneassymmetric carbon atom and R₄ is a straight chain alkyl group.
 8. Aferroelectric liquid crystal compound as claimed in claim 1, of theformula ##STR160##
 9. A ferroelectric liquid crystal compound as claimedin claim 1, of the formula ##STR161## wherein R₃ * is an alkyl groupcontaining just one assymmetric carbon atom and R₄ is a stright chainalkyl group.
 10. A ferroelectric liquid crystal compound as claimed inclaim 1, of the formula ##STR162## wherein R₃ * is an alkyl groupcontaining just one assymmetric carbon atom and R₄ is a striaght chainalkyl group.
 11. A ferroelectric liquid crystal compound as claimed inclaim 1, of the formula ##STR163## wherein R₃ * is an alkyl groupcontaining just one assymmetric carbon atom and R₄ is a straight chainalkyl group.
 12. A ferroelectric liquid crystal compound as claimed inclaim 1, of the formula ##STR164## wherein R₃ * is an alkyl groupcontaining just one assymmetric carbon atom and R₄ is a straight chainalkyl group.
 13. A ferroelectric liquid crystal compound as claimed inclaim 1, of the formula ##STR165## wherein R₃ * is an alkyl groupcontaining just one assymmetric carbon atom and R₄ is a straight chainalkyl group.
 14. A ferroelectric liquid crystal compound as claimed inclaim 1, of the formula ##STR166## wherein R₃ * is an alkyl groupcontaining just one assymmetric carbon atom and R₄ is a straight chainalkyl group.
 15. A ferroelectric liquid crystal compound as claimed inclaim 1, wherein one of R₁ and R₂ is a straight chain alkyl group of 5to 14 carbon atoms and the other is an alkoxyalkyl group containing justone asymmetric carbon atom which is located in the alkoxy portion of thealkoxyalkyl group.
 16. The compound of claim 2, which is(s)-5-n-octyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 17. Thecompound of claim 2, which is(s)-5-n-undecyl-2-[4-(2'-methylbutyloxy)phenyl]pyrimidine.
 18. Thecompound of claim 2, which is(s)-5-n-hexyl-2-[4-(3'-methylpentyloxy)phenyl]pyrimidine.
 19. Thecompound of claim 2, which is(s)-5-n-heptyl-2-[4-(3'-methylpentyloxy)phenyl]pyrimidine.
 20. Thecompound of claim 2, which is(s)-5-n-octyl-2-[4-(3'-methylpentyloxy)phenyl]pyrimidine.
 21. Thecompound of claim 2, which is(s)-5-n-nonyl-2-[4-(3'-methylpentyloxy)phenyl]pyrimidine.
 22. Thecompound of claim 2, which is(s)-5-n-decyl-2-[4-(3'-methylpentyloxy)phenyl]pyrimidine.
 23. Thecompound of claim 2, which is(s)-5-n-undecyl-2-[4-(3'-methylpentyloxy)phenyl]pyrimidine.
 24. Thecompound of claim 2, which is(s)-5-n-dodecyl-2-[4-(3'-methylpentyloxy)phenyl]pyrimidine.
 25. Thecompound of claim 2, which is(s)-5-n-hexyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 26. Thecompound of claim 2, which is(s)-5-n-heptyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 27. Thecompound of claim 2, which is(s)-5-n-octyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 28. Thecompound of claim 2, which is(s)-5-n-nonyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 29. Thecompound of claim 2, which is(s)-5-n-decyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 30. Thecompound of claim 2, which is(s)-5-n-undecyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 31. Thecompound of claim 2, which is(s)-5-n-dodecyl-2-[4-(4'-methylhexyloxgy)phenyl]pyrimidine.
 32. Thecompound of claim 2, which is(s)-5-n-tetradecyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 33. Thecompound of claim 2, which is(s)-5-n-hexyl-2-[4-(5'-methylheptyloxy)phenyl]pyrimidine.
 34. Thecompound of claim 2, which is(s)-5-n-heptyl-2-[4-(5'-methylheptyloxy)phenyl]pyrimidine.
 35. Thecompound of claim 2, which is(s)-5-n-octyl-2-[4-(5'-methylheptyloxy)phenyl]pyrimidine.
 36. Thecompound of claim 2, which is(s)-5-n-nonyl-2-[4-(5'-methylheptyloxy)phenyl]pyrimidine.
 37. Thecompound of claim 2, which is(s)-5-n-decyl-2-[4-(5'-methylheptyloxy)phenyl]pyrimidine.
 38. Thecompound of claim 2, which is(s)-5-n-undecyl-2-[4-(5'-methylheptyloxy)phenyl]pyrimidine.
 39. Thecompound of claim 2, which is(s)-5-n-dodecyl-2-[4-(5'-methylheptyloxy)phenyl]pyrimidine.
 40. Thecompound of claim 2, which is(s)-5-n-hexyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 41. Thecompound of claim 2, which is(s)-5-n-heptyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 42. Thecompound of claim 2, which is(s)-5-n-nonyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 43. Thecompound of claim 2, which is(s)-5-n-decyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 44. Thecompound of claim 2, which is(s)-5-n-undecyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 45. Thecompound of claim 2, which is(s)-5-n-dodecyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 46. Thecompound of claim 2, which is(s)-5-n-tetradecyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 47. Thecompound of claim 2, which is(R)-5-n-undecyl-2-[4-(2'-methylbutyloxy)phenyl]pyrimidine.
 48. Thecompound of claim 2, which is(R)-5-n-octyl-2-[4-(4'-methylhexyloxy)phenyl]pyrimidine.
 49. Thecompound of claim 3, which is(s)-5-n-octyl-2-[4-(6'-methyloctanoyloxy)phenyl]pyrimidine.
 50. Thecompound of claim 3, which is(s)-5-n-octyl-2-[4-(4'-methylhexanoyloxy)phenyl]pyrimidine.
 51. Thecompound of claim 3, which is(s)-5-n-undecyl-2-[4-(2'-methylbutanoyloxy)phenyl]pyrimidine.
 52. Thecompound of claim 3, which is(s)-5-n-undecyl-2-[4-(4'-methylhexanoyloxy)phenyl]pyrimidine.
 53. Thecompound of claim 3, which is(s)-5-n-undecyl-2-[4-(6'-methyloctanoyloxy)phenyl]pyrimidine.
 54. Thecompound of claim 3, which is(s)-5-n-tetradecyl-2-[4-(4'-methylhexanoyloxy)phenyl]pyrimidine.
 55. Thecompound of claim 3, which is(s)-5-n-tetradecyl-2-[4-(6'-methyloctanoyloxy)phenyl]pyrimidine.
 56. Thecompound of claim 4, which is(s)-5-n-octyl-2-[4-(6'-methyloctanyloxy)phenyl]pyrimidine.
 57. Thecompound of claim 5, which is(s)-5-n-octyl-2-[4-(3'-chloropentyloxy)phenyl]pyrimidine.
 58. Thecompound of claim 5, which is(s)-5-n-undecyl-2-[4-(3'-cyanopentyloxy)phenyl]pyrimidine.
 59. Thecompound of claim 6, which is(s)-5-n-hexyl-2-[4-(2'-methylbutyloxybutyloxy)phenyl]pyrimidine.
 60. Thecompound of claim 6, which is(s)-5-n-octyl-2-[4-(2'-methylbutyloxybutyloxy)phenyl]pyrimidine.
 61. Thecompound of claim 6, which is(s)-5-n-undecyl-2-[4-(2'-methylbutyloxybutyloxy)phenyl]pyrimidine. 62.The compound of claim 7, which is(s)-5-(n-undecyloxy)-2-[4-(2'-methylbutyloxy)phenyl]pyrimidine.
 63. Thecompound of claim 7, which is(s)-5-(n-octyloxy)-2-[4-(3'-methylheptyloxy)phenyl]pyrimidine.
 64. Thecompound of claim 7, which is(s)-5-(n-octyloxy)-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine.
 65. Thecompound of claim 7, which is(s)-5-(n-undecyloxy)-2-[4-(3'-methylheptyloxy)phenyl]pyrimidine.
 66. Thecompound of claim 7, which is(s)-5-(n-undecyloxy)-2-[4-(2'-methyloctyloxy)phenyl]pyrimidine.
 67. Thecompound of claim 8, which is(s)-5-(n-undecyloxy)-2-[4-(2'-methylbutanoyloxy)phenyl]pyrimidine. 68.The compound of claim 8, which is(s)-5-(n-octyloxy)-2-[4(2'-methylbutanoyloxy)phenyl]pyrimidine.
 69. Thecompound of claim 8, which is(s)-5-(n-octyloxy)-2-[4-(3'-methylheptanoyloxy)phenyl]pyrimidine. 70.The compound of claim 8, which is(s)-5-(n-octyloxy)-2-[4-(4'-methylhexanoyloxy)phenyl]pyrimidine.
 71. Thecompound of claim 8, which is(s)-5-(n-octyloxy)-2-[4-(6'-methyloctanoyloxy)phenyl]pyrimidine.
 72. Thecompound of claim 8, which is(s)-5-(n-undecyloxy)-2-[4-(3'-methylheptanoyloxy)phenyl]pyrimidine. 73.The compound of claim 9, which is(s)-2-(4-n-octyloxyphenyl)-5-(6'-methyloctyl)pyrimidine.
 74. Thecompound of claim 10, which is(s)-2-(4-n-octylphenyl)-5-(6'-methyloctyloxy)pyrimidine.
 75. Thecompound of claim 11, which is(s)-5-n-octyloxycarbonyl-2-[4-(6'-methyloctyloxy)phenyl]pyrimidine. 76.The compound of claim 12, which is(s)-5-(6'-methyloctyloxycarbonyl)-2-(4'-n-octyloxyphenyl)pyrimidine. 77.The compound of claim 13, which is(s)-2-(4-n-undecyloxyphenyl)-5-(2'methylbutyloxy)pyrimidine.
 78. Thecompound of claim 14, which is(s)-2-(4-n-undecanoyloxyphenyl)-5-(2'-methylbutyloxy)pyrimidine.